"Harass" is a good way to put it. I'm most certainly not the Apostle Paul, but I have chronic pain. I SO like the idea that it is a messenger of Satan harassing me. And it is written right here: "My grace is sufficient for you." I think I'll try believing that instead of in myself.

2 Corinthians 12:7-10
So to keep me from becoming conceited because of the surpassing greatness of the revelations, a thorn was given me in the flesh, a messenger of Satan to harass me, to keep me from becoming conceited.
Three times I pleaded with the Lord about this, that it should leave me.

But he said to me, “My grace is sufficient for you, for my power is made perfect in weakness.” Therefore I will boast all the more gladly of my weaknesses, so that the power of Christ may rest upon me.
For the sake of Christ, then, I am content with weaknesses, insults, hardships, persecutions, and calamities. For when I am weak, then I am strong.

Bible Gateway Link